In a hydraulically actuated clutch system such as often used in motor vehicles, there exists the problem that the clutch cannot be opened quickly enough especially at very low temperatures. It thus can happen that in a full brake application the engine becomes stalled. The reason for this is the high viscosity of the oil at low temperatures.
DE 196 39 377 has disclosed a control for an automatic clutch in which the transmissible torque, at gears or running steps having a high reduction ratio between engine rotational speed and rotational speed of the traction wheels and/or at low vehicle speed, exceeds the respective engine torque by a smaller amount than at gears or running steps with less reduction ratio and/or at higher vehicle velocity. The kinetic clutch torque follow up serves to improve the comfort and to minimize the shifting time.
In addition, U.S. Pat. No. 6,024,673 describes a brake-dependent clutch opening in which control instrument opens the clutch with a specific deceleration during a braking operation.
The problem on which this invention is based is to outline a method for clutch actuation at low temperatures which ensures a satisfactory operation of the clutch.